Welding cable and terminal assembly



Oct. 1, 1968 E, GROW; 3,404,369

WELDING CABLE AND TERMINAL ASSEMBLY Filed Sept. 1, 1966 i: kill.

INVENTOR. Zdr/Iral c BY /%M 52 United States Patehtofl 3,404,369 Patented Oct. 1, 1968 3,404,369 WELDING CABLE AND TERMINAL ASSEMBLY Earl I. Grove, Walled Lake, Mich., assignor to Gar Wood Industries, Inc., Wayne, Mich., a corporation of Michigan Filed Sept. 1, 1966, Ser. No. 576,666 2 Claims. (Cl. 339-223) ABSTRACT OF THE DISCLOSURE A flexible isopolarity cable is formed of metallic strands which are grouped into a plurality of rope sections. Each rope is encased in a rubber sleeve throughout most of its length, but the bare ends of the strands project beyond the rubber sleeves and all the strands of all ropes are compressed in and electrically connected to a tubular sheet metal terminal. The terminal has an integral flared skirt diverging from the portion which is compressed onto the strands and overlapping and compressed against all of the outer rubber sleeves in an area spaced from its free edge. Beyond such area and to its free edge the skirt is flared outwardly at a steeper angle.

The present invention relates to electrical conductors, and particularly to flexible conductor and terminal assemblies adapted to carry high amperage electric currents. The overall object of the invention is to provide an improved flexible conductor able to withstand repeated flexing about relatively short radii and suitable for the severe service conditions encountered by cables employed to conduct welding current to the electrodes of resistance welding machines.

A more specific object is to provide an improved cable and terminal assembly of the indicated character which attains an increased effective service life.

Other objects and advantages will become apparent upon consideration of the present disclosure in its entirety.

In the drawing:

FIGURE 1 is a perspective view of an electrical conductor constructed in accordance with the present invention; and

FIGURES 2, 3 and 4 are sectional views on a larger scale taken substantially as indicated by the lines and arrows II-II, IIIIII and IVIV respectively of FIG- URE 1. 7

Referring now to the drawing, my improved cable is designed to be employed without water cooling, and preferably is constructed of a plurality of separate ropes 10-16 inclusive, rather than being formed as a single large cable, even though all parts are of like polarity. Such subdivided construction is-employed in order to reduce the frictional wear between the strands. Each rope is comprised of a large number of fine strands of loosely twisted soft copper wire, for maximum flexibility, and each rope is preferably constructed in accordance with my United States Patent No. 3,079,460. Each rope is enclosed in a plastic sleeve 18 of a suitable elastomer such as soft synthetic rubber, the six ropes 10-15 being symmetrically grouped about a central core rope 16, and ropes 10-15 having an overall helical twist.

At each end the ropes extend beyond the sleeves and the cable is provided with a terminal or lug portion which may be formed of an initially cylindrical silver plated copper tube. A portion 22 of the terminal tube 20 is tightly compressed upon the bare extremities of the ropes to form anelectrical connection therewith. Such electrical connection portion 22 is pressed to rectangular form, as indicated in FIGURES 1 and 4, and may be drilled as indicated at 23 for attachment to a suitable terminal connector (unshown). This general method of forming a terminal lug portion is now known in the art, and as will be appreciated, the portions 22 are compressed under very high pressure to substantially eliminate spacing between the strands and form an efficient connection.

The terminal structure is provided with an integral flared skirt formed as a continuous rearward extension of the connecting portion 22 and generally designated 25. The skirt portion 25 substantially overlaps the rubber sleeves 18, which extend to a position relatively close to but spaced from the fully compressed connecting portion 22, as best illustrated in FIGURE 4. The rubber sleeves are secured with respect to the skirt. While such securance could be effected by means such as an adhesive, I have found it effective simply to compress the skirt portion sufficiently to grip the sleeves, as indicated in FIGURE 4. This is effected by extending the sleeves to a position relatively close to the fully compressed connecting section 22, and in an area 26 near its free edge the skirt is given a final flaring bend which also has the effect of forming a relatively pressed-in section near the free edge which constricts and grips the encircled portions of the rubber sleeves. The frictional engagement between the skirt portion 25 and the sleeves 18 is tight enough so that the sleeves cannot be pulled from the skirt or shift longitudinally with relation to the terminal or to each other under the forces resulting from flexing the cable.

The rubber sleeves 18 not only reduce friction between the individual ropes when the cable is flexed or distorted by electrical reactance, and function to reduce wear by preventing direct engagement between the skirt 25 and the ropes, but perform an additional mechanical function when the cable is bent in the area adjacent the terminal. At such times the forces transmitted through the sleeves 18, because of the fact that they are tightly held against longitudinal movement with relation to one another, force a larger proportion of the bending to occur farther away from the terminal, reducing localized bending and increasing the radius of bend. Highly localized forces tending to break the individual strands, and localized shortradius bending, are thus materially reduced.

In a conductor of this class wherein the ropes are individually sleeved despite being of the same polarity, the resultant spacing of the ropes also achieves an electrical benefit by reason of the reduction of impedance.

The terminal is preferably formed in suitable compression dies, and the excess metal resulting from the reduction of overall cross sectional area of the terminal tube is displaced inwardly in longitudinal lines along the side edges of the terminal, as indicated at 28.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects stated above, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or .fair meaning of the subjoined claims.

What is claimed is:

1. In a flexible isopolarity electrical cable assembly including a plurality of multi-strand conductor ropes, a'plurality of flexible sleeves, one on each rope, the sleeves being shorter than the ropes and a common end of all ropes projecting beyond their sleeves, and a connecting terminal comprising a metallic portion electrically connected to said projecting ends, the novelty which comprises a skirt portion rigid with said terminal and overlapping and secured with respect to all of said flexible sleeves.

2. An assembly as defined in claim 1 wherein the sleeves are formed of an elastomer and the terminal comprises a metal tube having at one end a connecting portion surrounding and compressed upon said projecting ends of the ropes, an integral intermediate skirt portion of greater perimeter compressed against the sleeves, and

3 4 an integral outwardly flared portion at its other end over- 2,480,280 8/1949 Bergan. lying and projecting away from the sleeves. 3,156,760 11/1964 Grove.

References Cited FOREIGN PATENTS UNITED STATES PATENTS 5 511,473 10/1930 Germany.

1,650,295 11/ 1927 Patten 339-223 LARAMIE E. ASKIN, Primary Examiner.

" 1,904,162 14/1933 Milliken. 

